Images and other forms of media are often accompanied by messages such as marking information in the form of a copyright or ownership notice, or reference information in the form of a uniform resource locator (URL). Such messages may be used, for instance, to prevent unauthorized use or distribution of the media, or to enhance a user's experience in connection with the media.
One common form of message is a visible watermark embedded in an image. A visible watermark, however, has significant drawbacks, as it may be distracting and obtrusive. An alternative, less obtrusive way of providing a message is by inserting it into an image file name or in metadata associated with an image. This approach also has significant drawbacks, however, since the message may be modified or lost through alteration of the image file name or metadata. For example, the message may be modified or lost when a system performs a memory size reduction operation by eliminating information that does not influence the actual rendering of the image for viewing.
In view of at least the above shortcomings of conventional approaches, there is a general need to provide messages in a form that is not distracting or obtrusive, yet is not easily removed or altered and can also be readily detected by programmatic means, e.g., without resorting to cumbersome detection mechanisms such as optical character recognition.